Stephen Lawrence's best friend broke down in tears at the Old Bailey today as he relived the horror of the teenager's murder by white racist thugs.

Duwayne Brooks, whose father had died overnight, shook with grief in the witness box and wiped away his tears with a handkerchief. He had insisted on coming to court to give evidence despite his family's bereavement.

Mr Brooks, now 37, showed the court how he saw18-year-old Stephen being cut down with a foot-long knife as the pair of them were set upon by a gang of white youths when they waited for a bus in Eltham 18 years ago.

He demonstrated the attack to the jury by lifting his right arm back above his head then bringing his clenched fist crashing down with force.

Mr Brooks said: "I don't know if you can call him the leader but the guy who had the weapon ran straight into him... and wham, just like that."

Then he told how he had been chased by one of the attackers wielding a metal bar in April 1993. Mr Brooks said the man carrying the metal bar then hit Stephen over the head with it.

The rest of the gang continued to attack Stephen before the chasing man broke off to return to where his victim lay prone and defenceless.

As the gang move off, Stephen struggled to his feet. Mr Brooks went on: "He jumps up and for a second I was re-lieved that nothing had happened.

"We ran up the road and we were running and he kept asking me to tell him what was wrong because he can not run properly.

"Blood was streaming out around his neck and through his jacket." At this point he broke down in tears - but even though prosecutor Mark Ellison, QC, offered him a break he replied: "No, I want to say."

His voice shaking with emotion, he went on: "He kept saying to me what happened to him, why was he running like that. Look at him, like I must tell him what's happened. Then we were running.

"I was frightened that ... the other guys would come back round. He started to sob again as he looked at a picture of the scene and described his best friend's dying word.

"He said one more time, 'Duwayne', and his voice was funny and he fell at that tree."

Mr Brooks said he desperately tried to raise the alarm and call for help. He raced to a telephone box but there was a mix-up with the 999 operator because the details of the exact location of the box were inaccurate.

After running back to his stricken friend, he found that passing motorists had stopped and were asking if an ambulance had been called.

Medical help arrived but despite the valiant efforts of everyone at the scene Stephen died from his massive blood loss.

Both the dead teenager's parents Neville and Doreen sat at the back of the court to hear the harrowing evidence from their son's friend.

Their son Stuart sat between them and appeared to wipe away a tear with his hand. Upstairs in the packed public gallery, women covered their eyes and two hugged each other.

The defendants made notes in the dock. One of them, David Norris, was wearing a hearing loop because of partial deafness.

The court heard that Stephen and Mr Brooks had been waiting with others at the bus stop at 10.30pm and were "chit chatting" about football.

The pair had gone up the road to see if they could spot the bus to take them home - or an alternative which might be quicker, even though it would go in a different direction.

They saw a group of young white males on the other side of the road. The violence broke out when the attackers hurled racist abuse at the teenagers, the jury was told.

Mr Brooks said: "These guys have come across the road and one of them said, 'What what n****r'." He added: "At the time I looked and I've seen where they are and I felt threatened. I started running back towards Shooters Hill and I said to Steve to run." Mr Brooks, wearing a blue shirt and tie, regained his composure as he continued to give his version of events for the rest of the morning.

Asked to describe the group of youths, he said: "At the time all I could say was they were all white, they were about the same age and they were all wearing jeans."

He said the person who shouted the racist remark at him was wearing a grey bomber jacket with white strips on either side.

Mr Brooks told the court he had suffered post traumatic stress dis-order after seeing his friend killed and continued to do so for at least two years after the attack.

He said he was no longer certain that he had seen the gang of white youths who had attacked them earlier that evening before the killing.

Giving evidence at a magistrates court in 1995, he said he had seen the same group earlier when he and Stephen had got off the No 286 bus near the Coronet cinema.

Today Mr Brooks said he had still been suffering from PTSD at the time he had given evidence in court.

"In a sense I was not in the right frame of mind. I can't say now that they were the same group of boys that attacked us," he told the Old Bailey.

Mr Brooks said certain parts of the attack were "too distressing, too scary and too upsetting".As a result, he had not immediately mentioned them to the police or in statements.

But over the years he has been able to "fill in the gaps" in his memory. Earlier, Mr Justice Treacy warned the jury not to read this week's edition of the Spectator magazine.

Norris, 35, and Gary Dobson, 36, both of south London, plead not guilty to murdering 18-year-old Stephen in April 1993. The case continues.